I have tried pressing to make her listen, it says "listening" but if I say "play radio" I just get a page of results from a web search for that phrase.
If I say "Launch FM Radio" then at least some of the time she does launch the app. However nothing further seems voice controllable - if the radio is paused, it doesn't care if I say "play" and certainly changing the channels isn't going to happen. If I try to embed a command to Cortana, like "launch FM Radio, Play" or "launch FM Radio and Play" we are just back in web search land.
Is it just something she can't do?